Cloning after Dolly
Professor Derek Burke
'Cloning' is a loose term used to describe everything from a new super race of identical nearrobots (remember 'The Boys from Brazil'?) to propagating your roses. It actually means a
twig, so it starts from the horticultural end, but is used much more widely.
Dolly was the first cloned mammal and must be the most famous sheep in the world. Two
things made her famous: first that she is an artificially induced clone, genetically identical to
a previously existing sheep, for Dolly can be thought of as a vertical twin with identical
genes, in this case to the parent. Second is the way in which it was done. The scientists took
the nucleus from a cell from the udder of an adult sheep and implanted it in an egg cell whose
original nucleus had been removed. Very surprisingly, the adult cell DNA was able to give
rise to a complete individual, not just more udder cells. This was surprising because, although
at the earliest stage of development the DNA is still pluripotent, capable of generating the
growth of the whole animal, later in development, specialization sets in, and cells become
differentiated into heart cells, liver cells etc. The whole of the genetic material is still there,
but most of it is switched off and only the genes relevant to that particular cell are active. It
had been thought that this process of differentiation in mammals was irreversible, so that an
udder cell could only give rise to more udder cells. But we now know that differentiation can
be reversed.
This work was undertaken for serious, responsible scientific reasons, but in the popular mind
the fuss was not generated by thoughts about animal cloning. It was the possibility of using
the same technique to clone humans that caught the lurid imagination of many, from visions
of worker clones, to the possibility of 'replacing' a dead parent or child. Of course such clones
would be new people; just try telling identical twins that they are only one person! But there
are some serious ethical issues to consider.
It is important to distinguish between reproductive cloning and therapeutic cloning which is
discussed in the next paper. Human reproductive cloning would be exactly like Dolly; it
would involve the creation of a cloned embryo which was then implanted in a woman's
womb to develop to term and the birth of a human clone. On the other hand, therapeutic
cloning would not result in the birth of a human clone, but would involve the growth of
cellular human tissue of specific kinds for treatment of disease or to replace non-functional
tissue or organs. It was reproductive cloning that all the fantastic speculations were about and
its possibility has rightly resulted in a great deal of unease.
The House of Commons Science and Technology Select Committee issued a report very soon
after the news of Dolly had become public, stating that there should be no creation of
'experimental human beings'. Reproductive human cloning would, in fact, be illegal in Britain
under the provisions of the Human Fertilisation and Embryology Act but to ensure that no
loophole remains, the current Government intends to introduce new legislation specifically
banning human reproductive cloning.
The European Bioethics Commission has called for the banning of reproductive human
cloning, asserting that every human being is entitled to their own individual and unique
genetic identity. While the conclusion may be valid, the reasoning is questionable. What
about identical twins? They are genetically indistinguishable, but no one doubts they are two
distinct and unique persons. The rights of one are not threatened by the existence of the other.
So, although we are constrained by our genetic inheritance, we are not determined by it.
Why are people so concerned?
1."Going where God alone should go?" Many feel uneasy about these developments because
they fear that natural barriers are being crossed; barriers that are dangerous or impious for
humanity to transgress. Are we in danger of attempting to usurp the prerogatives of the
Creator?
On the other hand, human beings have been intervening in nature to change 'natural'
processes for many years. Medicine and surgery are obvious examples. Christians can see
this activity, which is devoted to serious and beneficial ends, as an appropriate use of Godgiven human capacities, rather than an improper attempt to rival the Creator. Nevertheless,
not everything that can be done experimentally should be done. There is always the
possibility of the misuse of human powers.
2.Then there are those who are very concerned with animal rights, claiming that nothing
should be done to animals that is not for their individual good. They oppose animal cloning,
regarding the sorts of experiments that led to Dolly as being unacceptable. On the other hand,
those who believe that there is an ethically justifiable use of animals, for example, eating
meat, will not take so absolutist a view. They should, of course, insist that such activities
must ensure proper animal welfare, minimisation of suffering, and seriousness of purpose.
The Roslin experiments certainly fulfilled these criteria. In fact, cloned animals like Dolly are
of such value and significance that they can be expected to be cared for like gold for the rest
of their natural lives.
Cloning by nuclear transfer was first developed 40 years ago for frogs, and since the
successful cloning of Dolly, has been used to make clones of sheep, pigs, mice, cows and
goats and so technically it could probably be applied to people too. However the low
efficiency of the procedure may restrict it's immediate application even in animals - perhaps
to the production of small herds of identical animals, although other specialised uses can be
envisaged. For example, the technique could be used to inactivate potentially damaging prion
genes in cattle, and possibly for the resurrection of endangered species, notably the gaur and
possibly the bucardo, the Spanish mountain goat. (Nature 407, October12th, 2000, p. 666).
3. Another concern is about safety. In the experiments that led to Dolly, 277 attempts at
nuclear transplantation were made, but only 29 implantable embryos resulted and there was
only one completed pregnancy and birth - Dolly. This appears to be true of other such cloning
experiments. There is also some uncertainty about what 'age' Dolly will prove to be, her birth
age or the age of the ewe that provided the nucleus. Will cloned animal show increased
susceptibility to cancer and other diseases because their genes are already 'aged'? However,
the first mouse to be cloned from an adult cell died recently at the age of two years and seven
months, and since the average mouse's life is about two years, there does not seem to be
premature aging. (Nature, 405, May 18th, 2000, p 268.)
So even if human reproductive cloning were considered ethically acceptable on other
grounds, there would still be very severe questions about the safety of the procedure and the
degree of wastage that could occur. These questions could only be settled, first by extensive
animal investigations and then experiments with human subjects. This is also considered
ethically unacceptable.
However talk continues; The Times carried a two page spread on February 20th, 2001 headed
'I'm not a monster' which refers not to a human clone, but to an Italian, Professor Antinori,
who is President of the Italian Society of Reproductive Medicine, and who wants to 'clone'
humans by taking cells from the man's skin and fusing them with female egg cells extracted
from his wife's ovaries, after the original cell nucleus has been removed. The embryo, after
stimulation, is then to be reimplanted in the woman's womb. So the child, if one were to be
born, would be the natural child of those parents and would not be a clone, but the risks are
huge. He says that all he doing is finding a way around a barrier as in IVF, and that is true,
but he is being cavalier about the risks and Ian Wilmut, who cloned Dolly, says that the
proposals are 'irresponsible'. However despite the risk he says he has a long list of applicants
from all over the world.
Finally to go back to proper cloning. I think that many of the reasons suggested for human
reproductive cloning, such as replacement of lost kin or the perpetuation of particular
individuals, are not only fallacious because they fail to acknowledge the uniqueness of every
human person, but also they are totally ethically unacceptable because of their instrumental
treatment of the new human being. Every child that is born is to be valued for his or her own
sake and not as the replacement or perpetuation of another.
Similar objections must be made to proposals for the production of children whose genetic
make-up has been carefully crafted to the specifications of somebody else. Such 'designer
babies' would represent the ethically unacceptable commodification of children, but it is not
going to stop such attempts, especially in the United States where such experiments are only
forbidden if funded by the Federal Government not if they are funded from private sources.
It is clear that as our knowledge continues to expand we need increasing wisdom to know
where to draw lines between what can be done and what should be done.
Derek Burke